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(ModeL) S. W. WARDWELL, Jr. Manufacture of Sewed Articles of Leather.No. 235,050.

Patented Nov. 30,1880.

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arnNr MANUFACTURE OF SEWED ARTICLES OF LEATHER.

SPECIFICATION forming part of Letters Patent No. 235,050, dated November30, 1880.

Application filed April 8, 1880. (Model) I To all whom it may concern:

Be it known that I, SIMON W. WARDWELL, Jr., of Providence, Providencecounty, Rhode Island, have invented Improvements in the Manufacture ofSewed Articles of Leather, of which the following is a specification.

My improvement relates to a class of leather fabrics used in themanufacture of harness,

belting, and for other purposes, and especially in fine work heretoforesewed by hand, andin which several thicknesses of leather are securedtogether by being sewed with waxed threads; and my invention consists ofa fabric composed of two or more superposed pieces of leather sewedtogether with two threads which are covered with wax and are interlockedbetween the surfaces of the fabric and completely fill the perforationsthrough the fabric in which the two threads are respectively insertedfrom opposite sides.

It is not new to join superposed pieces of leather by machine-sewin gwith waxed thread; but as heretofore practiced the thread has beenlocked at one side of the fabric either by a chain-stitch or by anotherthread lying nearly parallel with or upon the surface of the fabric. Therib or chain of thread formed upon the surface of the fabric by eitherof these modes of sewing is especially exposed to wear, and when theinterlocked portion of the thread or threads is cut or worn away thestitches are disconnected into a series of separate loops having butlittle or no hold upon the fabric. In such modes of stitching thetension of the thread is usually insufficient, because of the difiicultyin drawing a tight tension upon a thread carried double entirely throughthe several thicknesses of leather.

Attem pts have heretofore been to ade to fasten together several piecesof leather by waxed threads interlocked between the exterior surfaces ofthe superposed pieces; but in these attempts the wax has been dissolved,stripped, or scraped from the thread in the act of sewing, the threadhas been untwisted, and the perforations through the fabric have beenmade larger than the heads formed by the bights of the interlockedthreads, which therefore were loosely contained in said perforations.

The characteristic features in my improved fabric which make itdistinguishable and give it su1i)eriority are, first, the union of theseveral thicknesses of leather by two threads interlocked within thebody of the fabric, whereby the interlocked portions are protected fromwear, and whereby any wax displaced from the surface of the interlockedportion is lodged against the central portion of the wall of theperforation in which the threads are deposited; second, the presence ofa wax coating upon all portions of the threads, both those which arevisible externally and those contained within the perforations, wherebythe absorption of water and consequent rotting of the threads areeffectually prevented third, the complete fillingof the perforationsofthe fabric by the waxed threads, which thus present the appearance ofand are in fact substantially like glued tenons, serving by theiradhesion to the walls of the perforations to hold together the severalthicknesses of leather of which the fabric is composed and prex'entingby the complete filling of the perforations the entrance of moisturetherein; fourth, the smallness of those parts of the perforation inwhich the parallel legs of each loop of thread are respectivelycontained in comparison with the central part of the perforation, whichis distended by the interlocking of the loops, the parallel legs of eachloop completely filling the awl-perforation on either side of the centerthereot'respectively, and the distended central part of the perforationbeing also completely filled by the interlocked bights of the loops,such interlocking forming a head so much larger than theawl-.perforation that it holds both loops and prevents either of themfrom being easily drawn out.

In conducting the manufacture of my improved fabric it is necessary thatthe machine employed shall be capable of forming a lockstitch, and thatthe mechanism of the machine shall be such that the waxed threads shallbe kept from contact with any oiled surfaces, which would dissolve thewax, and shall not be drawn over any relatively stationary surface orabrupt obstruction, which would scrape the wax off. It is especiallydesirable that there shall be the least possible movement of the threadwhile it is bent in the eye of the needle, and hence that there shouldbe the greatest possible reduction in the extent to which it is carriedthrough the material by the needle. The needle-thread should be passedthrough the material only far enough to permit it to be seized beneath,and the needle should ascend before the loop is made, so that the threadneed not be drawn along or in contact with the needle or through the eyeof the needle while the latter is within the perforation. By theemployment of these precautions the wax will neither be scraped nordissolved off the thread.

Finally, the perforations through the fabric should be made by an awl ofsmall area in cross-section, and the needle-thread should be carried bya very thin needle. Any tendency of the downwardly-projecting portion ofthe needle to bend or spring out of alignment with the looper may beprevented by the use of a gage beneath the fabric. A needle maytherefore be used which is proportionately so fine that theawl-perforation need only be large enough to receive the thread alone,the fabric being sufficiently elastic to yield when the needle and itsthread enter the perforation, and being suffieiently resilient to closearound the threads after the needle is withdrawn.

in the accompanyingdrawings,representing a fabric embodying myinvent-ion, Figure l is an isometrical perspective ofa fabric composedof superposed strips or sheets of leather secured together by two waxedthreads interlocked within the body of the fabric, a portion of thesurface of the fabric being shaved off, and exhibiting the shape incross-section of the perforations and the complete packing of theperforations by theinserted threads. Fig. 2 is a transverse section ofthe fabric through a line of stitches upon a magnified scale, furtherillustrating the packing of the perforations by the waxed threads andthe shape of the perforations in which the threads are packed.

It will, of course, be understood that the number of stitches to theinch and the number of thicknesses of leather of which my improvedfabric is composed may be varied at will without departing from myinvention.

The drawings represent a fabric made of two superposed sheets ofleather, A and B, secured tLogCether by three parallel rows of stitches,C

A portion, a, of the fabric is represented as having been shaved downfrom the surface for the purpose of exhibiting the contour of the 11erforations D and the complete filling of these perforations by thelooped portions 0 of the waxed threads.

It will be observed that the interlocked bights form the knot or head 0,which enlarges the middle part of the perforation and serves to hold thestitching in the fabric.

My improved fabric may be manufactured by the employment of any suitablemechanism having the capacity of operation hereinbefore set forth butthat which I prefer, and which I have invented for the purpose,'is fullyshown and described in Letters Patent of the United States No. 218,464,dated August 12, 1879, granted to me for improvement in wax-threadsewing-machines.

I claim- I 1. As a new article of manufacture, a fabric made of two ormore thicknesses of leather, sewed together by two wax-coated threads,respectively entering from opposite sides within and completely fillingtransverse perforations in the fabric and interlocked between theopposite surfaces thereof, substantially as and for the purpose setforth.

2. The combination, in an article of leather, of two or more layers ofleather with two interlocked wax threads, respectively inserted fromopposite sides in and tightly filling series of openings through thesuperposed parts of the leather, and by their interlocking forming headslarger in cross-area than those parts of the perforations in which theparallel portions of the thread are packed, substantially as set forth.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

SIMON W. WAItDl/VELL, JR.

\Vitnesses:

NELsoN P. EDDY, FRED. H. Brsnor.

